This invention relates to novel anthranilic acid derivatives having pharmacological activity, to a process for their production, to a pharmaceutical composition containing the same, and to their use as a medicament.
It is known that a cyclic guanosine-3xe2x80x2,5xe2x80x2-monophosphate (hereinafter referred to as cGMP) derived from a guanosine-5xe2x80x2-triphosphate possesses a relaxant activity of smooth muscle and that a cyclic guanosine-3xe2x80x2,5xe2x80x2-monophosphate phosphodiesterase (hereinafter refereed to as cGMP-PDE) acts to catalyze the degradation of cGMP to a guanosine-5xe2x80x2-monophosphate. The compounds having an inhibitory activity of cGMP-PDE are disclosed in European Patent Publication Nos. 579,496; 534,443; 526,004; 636,626; U.S. Pat. Nos. 3,819,631; 5,294,612; 5,488,055; International Patent Publication Nos. 93/07,124; 94/19,351; 95/18,097; 96/32,379; Japan Patent Publication Nos. 05-222,000; 07-330,777; and so on.
This invention relates to novel anthranilic acid derivatives, which have pharmaceutical activity such as inhibiting activity of cGMP-PDE, to a process for their production, to a pharmaceutical composition containing the same and to a use thereof.
Accordingly, one object of this invention is to provide the novel anthranilic acid derivatives, which have an inhibiting activity of cGMP-PDE.
Another object of this invention is to provide a process for production of the anthranilic acid derivatives.
A further object of this invention is to provide a pharmaceutical composition containing, as an active ingredient, an anthranilic acid derivative.
Still further object of this invention is to provide a use of the anthranilic acid derivatives for treating or preventing various diseases.
The new anthranilic acid derivatives of this invention can be represented by the following formula (I): 
wherein
R1 is hydrogen atom or a halogen atom;
R2 is an electron withdrawing group;
R3 is hydrogen atom; hydroxy group; a lower alkoxy group; a cycloalkyl group; a substituted or unsubstituted aryl group; or an unsaturated heterocyclic group optionally substituted with lower alkyl;
A is a lower alkylene group;
R4 is a lower alkoxy group,
a substituted or unsubstituted, saturated or unsaturated heterocyclic group,
an amino group optionally substituted with halo(lower)alkyl or lower alkyl,
a group xe2x80x94CH2xe2x80x94R5 
wherein R5 is a cycloalkyl group or an unsaturated heterocyclic group, or
a group xe2x80x94CR6R7R8 wherein
R6 and R7 are each independently carboxy group,
a protected carboxy group,
a carbamoyl group optionally substituted with lower alkyl, or
a lower alkyl group optionally substituted with one or more substituents selected from the group consisting of halogen atom; hydroxy group; cyano group; azido group; lower alkoxy group; lower alkylthio group; protected carboxy group; lower alkanesulfonyl group; acyloxy group; lower alkanesulfonyloxy group; aryl group; aryloxy group which may be substituted with cyano; unsaturated heterocyclic group which may be substituted with lower alkyl; guanidino group which may be substituted with lower alkyl, cyano and/or halogen; isothioureido group which may be substituted with lower alkyl and/or cyano; and amino group which may be substituted with acyl, protected carboxy, lower alkanesulfonyl, lower alkanesulfonyloxy or aryloxycarbonyl, or
R6 and R7 together with the carbon atom to which R6 and R7 are attached may form a substituted or unsubstituted, saturated carbocyclic group, or an unsaturated carbocyclic group optionally substituted with hydroxy, and
R8 is hydrogen atom; a lower alkoxy group; or a lower alkyl group optionally substituted with hydroxy or lower alkoxy;
provided that
when R4 is the group xe2x80x94CR6R7R8 wherein
R6 is a lower alkyl group optionally substituted with halogen,
R7 is a lower alkyl group optionally substituted with halogen,
and R8 is hydrogen atom or a lower alkyl group, or when R4 is the group xe2x80x94CH2xe2x80x94R5 wherein R5 is the same as the above, R3 should be hydrogen atom, hydroxy group or a cycloalkyl group; and a pro-drug thereof, and a salt thereof.
The compounds of the formula (I) may contain one or more asymmetric centers and thus they can exist as enantiomers or diastereoisomers.
The compounds of the formula (I) may also exist in tautomeric forms and the invention includes both mixtures and separate individual tautomers.
It is further to be noted that isomerization or rearrangement of the compounds (I) may occur by the effect of light, acid, base or the like, and the compounds obtained as the result of said isomerization or rearrangement are also included within the scope of the present invention.
The compounds of the formula (I) and its salts can be in the form of a solvate, which is included within the scope of the present invention. The solvate preferably include a hydrate and an ethanolate.
Also included in the scope of invention are radiolabelled derivatives of compounds of formula (I) which are suitable for biological studies.
According to this invention, the object compounds (I) or its salts can be prepared by the following process. 
In the above formulae, R1, R2, R3, R4, R6, R7 and A are the same as those defined in the above.
Some of the starting materials are novel and can be prepared by the following processes. 
In the above formulae, R1, R2, R3, R4, R6, R7 and A are the same as those defined in the above, R is hydrogen atom or a lower alkyl group.
In the above and subsequent descriptions of the present specification, suitable examples and illustrations of the various definitions which the present invention includes within the scope are explained in detail in the following.
The term xe2x80x9clowerxe2x80x9d is intended to mean a group having 1 to 6 carbon atom(s), unless otherwise indicated.
Suitably the lower alkyl groups and lower alkyl moieties in the terms of the halo(lower)alkyl, lower akanesulfonyl, lower alkanesulfonyloxy, lower alkoxy, lower alkylthio, hydroxy(lower)alkyl, ar(lower)alkyl, ar(lower)alkoxy and ar(lower)alkoxycarbonyl groups may include straight or branched ones having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl or the like, more suitably the ones having 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl or isobutyl.
Suitably the examples of the lower alkenyl groups include straight or branched ones having 2 to 6 carbon atoms, such as ethenyl, propenyl (i.e., allyl or 1-propenyl), butenyl, isobutenyl, pentenyl, hexenyl or the like.
Suitable lower alkylene groups and lower alkylene moieties in the lower alkylenedioxy group may include straight or branched ones having 1 to 6 carbon atoms, such as methylene, methylmethylene, ethylene, methylethylene, trimethylene, tetramethylene, 2-methyltrimethylene, pentamethylene, hexamethylene or the like, more suitably the ones having 1 to 3 carbon atoms.
Suitable examples of the acyl groups and acyl moieties in the term of the acyloxy group include aliphatic acyl groups such as lower alkanoyls (e.g., formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, oxalyl, succinyl or pivaloyl) and acyl groups containing an aromatic or heterocyclic ring such as aroyls (e.g., benzoyl, toluoyl, xyloyl or naphthoyl), ar(lower)alkanoyls (e.g., phenylacetyl or phenylpropionyl), ar(lower)alkoxycarbonyls (e.g., benzyloxycarbonyl or phenethyloxycarbonyl), heterocyclic carbonyls (e.g., thenoyl or furoyl) and the like.
The cycloalkyl groups may include the ones having 3 to 7 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or the like.
Suitably the aryl groups and aryl moieties in the terms of the ar(lower)alkyl, ar(lower)alkoxy, aryloxy, aryloxycarbonyl and aroyloxy groups may be an aromatic group having 6 to 12 carbon atoms. Specific examples thereof are phenyl, naphthyl, indenyl, azulenyl, biphenylenyl, fluorenyl and anthracenyl.
Suitable examples of the saturated carbocyclic groups may be the cycloalkyl groups as exemplified in the above.
Suitable examples of unsaturated carbocyclic groups may include cyclopentenyl, cyclohexenyl, cycloheptenyl, 2,3-dihydro-1H-indenyl, benzocyclohexyl and the like.
Suitable examples of the halogen atoms and halo moiety of the halo(lower)alkyl group may be fluorine, chlorine, bromine or iodine.
Suitable examples of the unsaturated heterocyclic group may include mono- or poly-cyclic groups containing at least one hetero atom selected from nitrogen, sulfur and oxygen atoms, such as
(1) unsaturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing 1 to 4 nitrogen atoms, for example, pyrrolyl, pyrrolinyl, imidazolyl, pyrazolyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazolyl [e.g., 4H-1,2,4-triazolyl, 1H-1,2,3-triazolyl or 2H-1,2,3-triazolyl], tetrazolyl [e.g., 1H-tetrazoly or 2H-tetrazolyl] or the like.;
(2) unsaturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing an oxygen atom, for example, pyranyl or furyl;
(3) unsaturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing 1 to 2 sulfur atoms, for example, thienyl or the like
(4) unsaturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms, for example, oxazolyl, isoxazolyl, oxadiazolyl [e.g., 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl or 1,2,5-oxadiazolyl] or the like;
(5) unsaturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms, for example, thiazolyl, thiadiazolyl [e.g., 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl or 1,2,5-thiadiazolyl] or the like;
(6) unsaturated condensed heterocyclic groups containing 1 to 2 nitrogen atoms, for example, indolyl, indazolyl, quinolyl, isoquinolyl, quinazolinyl, quinoxalinyl, benzimidazolyl or the like;
(7) unsaturated condensed heterocyclic groups containing 1 to 2 oxygen atoms, for example, benzofuryl or the like;
(8) unsaturated condensed heterocyclic groups containing 1 to 2 sulfur atoms, for example, benzo[b]thienyl or the like;
(9) unsaturated condensed heterocyclic groups containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms, for example, benzoxazolyl, benzoxadiazolyl, phenoxazinyl or the like;
(10) unsaturated condensed heterocyclic groups containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms, for example, benzothiazolyl, benzoisothiazolyl, phenothiazinyl or the like.
Suitable examples of the saturated heterocyclic group and heterocyclic moiety in the saturated heterocyclic sulfonyl group include monocyclic groups containing at least one hetero atom selected from nitrogen, sulfur and oxygen atoms, such as
(1) saturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing 1 to 4 nitrogen atoms [e.g., pyrrolidinyl, imidazolidinyl, piperidyl or piperazinyl];
(2) saturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing 1 to 2 oxygen atoms and 1 to 3 nitrogen atoms [e.g., morpholinyl];
(3) saturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing 1 to 2 sulfur atoms and 1 to 3 nitrogen atoms [e.g., thiazolidinyl or thiomorpholinyl];
(4) saturated 3 to 7-membered, preferably 5 or 6-membered heteromonocyclic groups containing 1 to 2 sulfur atoms and/or 1 to 2 oxygen atoms [e.g., tetrahydrothiophenyl, tetrahydrothiopyranyl, 1-oxotetrahydrothiopyranyl, 1,1-dioxotetrahydrothiopyranyl, dioxacyclohexyl, tetrahydrofuranyl, tetrahydropyranyl or dioxanyl]; or the like.
Suitably carboxy protective groups in the protected carboxy group may include lower alkyl groups (e.g., methyl, ethyl or tert-butyl), halo(lower)alkyl groups (e.g., 2-iodomethyl or 2,2,2-trichloroethyl), ar(lower)alkyl groups (e.g., benzyl, trityl, 4-methoxybenzyl, 4-nitrobenzyl, phenethyl, bis(methoxyphenyl)methyl, 3,4-dimethoxybenzyl or 4-hydroxy-3,5-di-tert-butylbenzyl), aryl groups (e.g., phenyl, naphthyl, tolyl or xylyl), and the like, more suitably the lower alkyl groups such as methyl, ethyl or tert-butyl and ar(lower)alkyl groups such as benzyl.
Specific examples of the each group containing the above-mentioned moiety and having substituent(s) are as follows.
As the halo(lower) alkyl group, fluoromethyl, iodomethyl, chloromethyl, trifluoromethyl, difluoromethyl, trichloromethyl, 2,2,2-trifluoroethyl, 2,2,2-trichloroethyl or the like may be mentioned.
The lower alkanesulfonyl group is methanesulfonyl(mesyl), ethanesulfonyl, propanesulfonyl or the like.
The lower alkanesulfonyloxy group is methanesulfonyloxy(mesyloxy), ethanesulfonyloxy, propanesulfonyloxy or the like.
The lower alkoxy group is methoxy, ethoxy, propoxy, n-butoxy, tert-butoxy of the like.
The lower alkylthio group is methylthio, ethylthio, propylthio, butylthio, isobutylthio or the like.
The acyloxy group is formyloxy, acetyloxy, propionyloxy, benzoyloxy, toluoyloxy, naphthoyloxy, phenylacetyloxy, theonyloxys or the like.
The hydroxy(lower)alkyl group is hydroxymethyl, hydroxyethyl or the like.
The ar(lower)alkyl group is benzyl, 4-methoxybenzyl, 4-nitrobenzyl, phenethyl, trityl, bis(methoxyphenyl)methyl, 3,4-dimethoxybenzyl, 4-hydroxy-3,5-di-tert-butylbenzyl) or the like.
The ar(lower)alkoxy group is benzyloxy, 4-methoxybenzyloxy, 4-nitrobenzyloxy, phenethyloxy, trityloxy, bis(methoxyphenyl)methoxy, 3,4-dimethoxybenzyloxy, 4-hydroxy-3,5-di-tert-butylbenzyloxy or the like.
The lower alkylenedioxy group is methylenedioxy, ethylenedioxy and the like.
The aryloxy group is phenoxy, naphthoxy, tolyloxy, xylyloxy or the like.
The aroyloxy group is benzoyloxy, naphthoyloxy or the like.
The saturated heterocyclic sulfonyl group is piperazinesulfonyl, piperizinesulfonyl, morpholinesulfonyl, pyrazolidinesulfonyl or the like.
Preferred embodiments of the compounds (I) are those represented by the formula (I),
wherein
R1 is hydrogen atom or a halogen atom;
R2 is an electron withdrawing group;
R3 is hydrogen atom; hydroxy group; a lower alkoxy group; a cycloalkyl group; a substituted or unsubstituted aryl group; or an unsaturated heterocyclic group optionally substituted with lower alkyl;
A is a lower alkylene group;
R4 is a lower alkoxy group,
a substituted or unsubstituted, saturated or unsaturated heterocyclic group,
an amino group optionally substituted with halo(lower)alkyl or lower alkyl,
a group xe2x80x94CH2xe2x80x94R5 
wherein R5 is a cycloalkyl group or an unsaturated heterocyclic group, or
a group xe2x80x94CR6R7R8 wherein
R6 and R7 are each independently carboxy group,
a protected carboxy group,
a carbamoyl group optionally substituted with lower alkyl, or
a lower alkyl group optionally substituted with one or more substituents selected from the group consisting of halogen atom; hydroxy group; cyano group; azido group; lower alkoxy group; lower alkylthio group; protected carboxy group; lower alkanesulfonyl group; acyloxy group; lower alkanesulfonyloxy group; aryl group; aryloxy group which may be substituted with cyano; unsaturated heterocyclic group which may be substituted with lower alkyl; guanidino group which may be substituted with lower alkyl, cyano and/or halogen; isothioureido group which may be substituted with lower alkyl and/or cyano; and amino group which may be substituted with acyl, protected carboxy, lower alkanesulfonyl, lower alkanesulfonyloxy or aryloxycarbonyl, or
R6 and R7 together with the carbon atom to which R6 and R7 are attached may form a substituted or unsubstituted,
saturated carbocyclic group, or
an unsaturated carbocyclic group optionally substituted with hydroxy, and
R8 is hydrogen atom; a lower alkoxy group; or a lower alkyl group optionally substituted with hydroxy or a lower alkoxy;
provided that
when R4 is the group xe2x80x94CR6R7R8 wherein
R6 is a lower alkyl group optionally substituted with halogen,
R7 is a lower alkyl group optionally substituted with halogen,
and R8 is hydrogen atom or a lower alkyl group, or
when R4 is the group xe2x80x94CH2xe2x80x94R5 wherein R5 is the same as the above, R3 should be hydrogen atom, hydroxy group or a cycloalkyl group, the electron withdrawing group for R2 being selected from a group consisting of nitro group; cyano group; acyl group; halo(lower)alkyl group; sulfamoyl group; carbamoyl group optionally substituted with lower alkyl; halogen atom; lower alkenyl group optionally substituted with protected carboxy; lower alkanesulfonyl group; saturated heterocyclic sulfonyl group optionally substituted with protected carboxy; and unsaturated heterocyclic group,
the substituent(s) on the aryl group for R3 being selected from a group consisting of lower alkyl group; halo(lower)alkyl group; lower alkylthio group; halogen atom; hydroxy group; lower alkylenedioxy group; cyano group; nitro group; carboxy group; protected carboxy group; sulfamoyl group; acyl group; aryl group; ar(lower)alkoxy group; aryloxy group; lower alkoxy group which may be substituted with lower alkoxy or cycloalkyl; amino group which may be substituted with acyl, protected carboxy or lower alkyl; and carbamoyl group which may be substituted with lower alkyl,
the substituent(s) on the saturated or unsaturated heterocyclic group for R4 being selected from a group consisting of oxo group; acyl group; protected carboxy group; lower alkanesulfonyl group; sulfamoyl group which may be substituted with protected carboxy; ar(lower)alkyl group; lower alkyl group which may be substituted with hydroxy or aryl; ureido group which may be substituted with lower alkyl; guanidino group which may be substituted with protected carboxy; amidino group which may be substituted with protected carboxyl; and carbamoyl group which may be substituted with lower alkyl, and
the substituent(s) on the saturated carbocyclic group formed by combination of R6 and R7 being selected from a group consisting of lower alkyl group; halogen atom; hydroxy group; lower alkoxy group; acyloxy group; carboxy group; protected carboxy group; oxo group; amidino group which may be substituted with protected carboxy; ureido group which may be substituted with lower alkyl or aryl; guanidino group which may be substituted with protected carboxy; amino group which may be substituted with acyl, lower aLkanesulfonyl or protected carboxy; and carbamoyl group which may be substituted with lower alkyl or hydroxy(lower)alkyl;
and a pro-drug thereof, and a salt thereof.
Another preferred embodiments are as follows: compounds of the formula (I),
wherein
R1 is hydrogen atom or a halogen atom;
R2 is an electron withdrawing group;
R3 is a substituted or unsubstituted aryl group;
A is a lower alkylene group; and
R4 is a group xe2x80x94CR6R7R8 wherein
R6 and R7 together with the carbon atom to which R6 and R7 are attached may form a substituted or unsubstituted, saturated carbocyclic group, and
R8 is hydrogen atom; and
compounds of the formula (I), wherein
R1 is hydrogen atom or a halogen atom;
R2 is an electron withdrawing group;
R3 is a substituted or unsubstituted aryl group;
A is a lower alkylene group; and
R4 is a group xe2x80x94CR6R7R8 wherein
R6 is a lower alkyl group substituted with hydroxy,
R7 is a lower alkyl which may be substituted with hydroxy, and
R8 is hydrogen atom or a lower alkyl group which may be substituted with hydroxy.
Further preferred embodiments are as follows: compounds of the formula (I), wherein
R1 is hydrogen atom or a halogen atom;
R2 is nitro group, cyano group or a halo(lower)alkyl group;
R3 is an aryl group optionally substituted with one or more substituent(s) selected from halogen and lower alkoxy;
A is a lower alkylene group; and
R4 is a group xe2x80x94CR6R7R8 wherein
R6 and R7 together with the carbon atom to which R6 and R7 are attached may form a saturated carbocyclic group optionally substituted with hydroxy or amino which may be substituted with acyl; and
R8 is hydrogen atom; and
compounds of the formula (I), wherein
R1 is hydrogen atom or a halogen atom;
R2 is nitro group, cyano group or a halo(lower)alkyl group;
R3 is an aryl group optionally substituted with one or more substituent(s) selected from halogen and lower alkoxy;
A is a lower alkylene group; and
R4 is a group xe2x80x94CR6R7R8 wherein
R6 is a lower alkyl group substituted with hydroxy,
R7 is a lower alkyl group which may be substituted with hydroxy, and
R8 is hydrogen atom or a lower alkyl group which may be substituted with hydroxy.
In accordance with the invention, it includes salts of the compounds (I). The salts may be conventional non-toxic pharmaceutically acceptable salts, for example, a salt with an alkali metal (e.g., sodium or potassium) and an alkaline earth metal (e.g., calcium or magnesium), an ammonium, an organic base (e.g., trimethylamine, triethylamine, pyridine, picoline, dicyclohexylamine or dibenzylethylenediamine), an organic acid (e.g., acetic acid, benzoic acid, succinic acid, fumaric acid, maleic acid, lactic acid, citric acid, tartaric acid, gluconic acid, methanesulfonic acid, benzenesulifonic acid, formic acid, p-toluenesulfonic acid or trifluoroacetic acid), inorganic acid (e.g., hydrogen chloride, hydrogen bromide, sulfuric acid or phosphoric acid), an amino acid (e.g., arginine, aspartic acid or glutamic acid) or the like.
The processes for preparing the starting compounds and the object compounds (I) of the present invention are explained in detail in the following.
A compound (I) or its salt can be prepared by reacting a compound (II) or its salt with a compound (II) or its salt.
This reaction is usually carried out in the presence of an inorganic or an organic base.
Suitable inorganic base may include an alkali metal [e.g., sodium or potassium], an alkali metal hydroxide [e.g., sodium hydroxide or potassium hydroxide], an alkali metal hydrogen carbonate [e.g., sodium hydrogen carbonate or potassium hydrogen carbonate], an alkali metal carbonate [e.g., sodium carbonate], an alkali earth metal carbonate [e.g., calcium carbonate], an alkali metal hydride [e.g., sodium hydride or potassium hydride] and the like.
Suitable organic base may include tri(lower)alkylamines [e.g., triethylamine or N,N-diisopropylethylamine], alkyl lithiums [e.g., methyl lithium or butyl lithium], lithium diisopropylamide, lithium hexamethyldisilazido and the like.
The reaction is usually carried out in a conventional solvent such as water, alcohols [e.g., methanol, ethanol or isopropyl alcohol], tetrahydrofuran, dioxane, toluene, methylene chloride, chloroform, N,N-dimethylformamide or any other organic solvent which does not adversely affect the reaction, or a mixture thereof.
The reaction is preferably carried out at a temperature under cooling to warming. However, the reaction temperature is not limited.
A compound (I) or its salt can be prepared by reacting a compound (IV) or its reactive derivative at the carboxy group, or its salt, with a compound (V) or its reactive derivative at the amino group, or its salt, according to a procedure known in the art.
Suitable reactive derivatives at the carboxy group of the compound (IV) may include the acid chloride, azide, acid anhydride, activated amide, activated ester and the like.
Suitably the acid anhydride may include anhydrides with an acid such as substituted phosphoric acid (e.g., dialkylphosphoric acid, phenylphosphoric acid, diphenylphosphoric acid, dibenzylphosphoric acid or halogenated phosphoric acid), dialkylphosphorous acid, sulfuric acid, thiosulfuric acid, alkanesulfonic acid (e.g., methanesulfonic acid or ethanesulfonic acid), alkanoic acid (e.g., pivalic acid, pentanoic acid or isopentanoic acid), aromatic carboxylic acid (e.g., benzoic acid, chlorobenzoic acid, fluorobenzoic acid or nitrobenzoic acid), or the like.
Suitably the active amide may include the imidazoylylamide, 4-substituted imidazoylylamide, dimethylpyrazolylamide, triazolylamide tetrazolylamide or the like.
Suitably the active ester may include the dimethyliminomethyl [(CH3)2N+xe2x95x90CHxe2x80x94] ester, vinyl ester, propargyl ester, 4-nitrophenyl ester, 2,4-dinitrophenyl ester, trichlorophenyl ester, pentachlorophenyl ester, pentafluorophenyl ester, methanesulfonylphenyl ester, phenyl thioester, p-nitrophenyl thioester, carboxymethyl thioester, pyranyl ester, pyridyl ester, 8-quinolyl thioester, an ester with a N-hydroxy compound (e.g., N,N-dimethylhydroxylamine, 1-hydroxy-2H-pyridone, N-hydroxysuccinimide, N-hydroxybenzotriazole or N-hydroxyphthalamide) or the like.
Suitably the reactive derivative at amino group of the compound (V) may include Schiff""s base type imino or its tautomeric enamine type isomer formed by the reaction of the compound (V) with a carbonyl compound such as aldehyde, ketone or the like; a silyl derivative formed by the reaction of the compound (V) with a silylating reagent such as trimethylsilylchloride, N,O-bis(trimethylsilyl)acetamide, N-trimethylsilylacetamide or the like.
Each reactive derivative of compounds (IV) and (V) can optionally be selected from the above according to the kinds of the compounds (IV) and (V) to be used, respectively.
When the compound (IV) is used in a free acid form or its salt form in the reaction, the reaction is preferably carried out in the presence of a condensing agent.
Suitable condensing agent may include carbodiimides (e.g., N,N-dicyclohexylcarbodiimide, N-cyclohexyl-Nxe2x80x2-(4-diethylaminocyclohexyl)carbodiimide or N-ethyl-Nxe2x80x2-(3-dimethylaminopropyl)carbodiimide or its hydrochloride), diphenylphosphinic azide, diphenylphosphinic chloride, diethylphosphoryl cyanide, bis(2-oxo-3-oxazolidinyl)phosphinic chloride, N,Nxe2x80x2-carbonyldiimidazole, 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline, cyanuric chloride or the like.
The reaction may be also carried out in the presence of an organic or inorganic base such as an alkali metal carbonate, tri(lower)alkylamine, pyridine, N-(lower)alylmorphorine or the like.
The reaction is usually carried out in a conventional solvent such as water, acetone, alcohols [e.g., methanol, ethanol or isopropyl alcohol], tetrahydrofuran, dioxane, toluene, methylene chloride, chloroform, N,Nxe2x80x2-dimethylformamide or any other organic solvent which does not adversely affect the reaction, or a mixture thereof.
The reaction is preferably carried out at a temperature under cooling to warming. However, the reaction temperature is not limited.
A compound (I-1) or its salt can be prepared by reacting a compound (VI) or its salt with a ketone compound (VII) in the presence of an inorganic acid (e.g., sulfuric acid or hydrogen chloride) or an organic acid (e.g., acetic acid) and a reducing agent.
Suitable reducing agent may include sodium cyanoborohydride, sodium triacetoxyborohydride, sodium borohydride, borane-pyridine complex and the like.
The reaction is usually carried out in a conventional solvent such as alcohols (e.g., methanol or ethanol), tetrahydrofuran, dioxane, toluene or any other organic solvent which does not adversely affect the reaction, or a mixture thereof.
The reaction is preferably carried out at a temperature under cooling to ambient temperature. However, the reaction temperature is not limited.
Instead of the ketone compound (VII), its corresponding aldehyde may be used in this reaction.
Process A
The process A can be carried out in a manner similar to Process 2 by using a 2-fluorobenzoic acid derivative (VIII) and an amine compound (V) to obtain the compound (1).
Process B
The process B can be carried out in a manner similar to Process 3 by using an aminobenzoate derivative (IX) and a ketone compound (VII) to obtain the compound (IV-1).
Process C
The process C can be carried out in a manner similar to Process 1 by using a 5-fluorobenzoate derivative (X) and an amine compound (III) to obtain the compound (IV).
Process D
The compound (VI) can be prepared by reacting an isatoic anhydride derivative (XI) with an amine compound (V).
This reaction is usually carried out in a conventional solvent such as acetone, tetrahydrofuran, dioxane, toluene, methylene chloride, chloroform, N,Nxe2x80x2-dimethylformamide or any other organic solvent which does not adversely affect the reaction, or a mixture thereof.
The reaction is preferably carried out at a temperature under cooling to ambient temperature. However, the reaction temperature is not limited.
A pharmaceutically acceptable salt of the compound (I) can be prepared by treating a compound (I) with an appropriate base or acid in accordance with the conventional method.
The compounds (I) and pharmaceutically acceptable salts thereof possess inhibitory activity of cGMP-PDE (especially PDE-V), relaxant activity of smooth muscle, bronchodilator activity, vasodilative activity, relaxant activity of the penile corpus cavernosum, inhibitory activity of smooth muscle cells proliferation, inhibitory activity of allergy, and so on.
The compounds (I) and pharmaceutically acceptable salts thereof, therefore, are useful for the treatment and/or prevention of various diseases, such as angina, hypertension, pulmonary hypertension, congestive heart failure, glomerular diseases (e.g., diabetic glomerulosclerosis), renal tubulo-intestitinal diseases (e.g., nephropathy induced by tacrolimus, cyclosporin or the like), renal failure, atherosclerosis, conditions of reduced blood vessel patency (e.g., post-percutaneous transluminal coronary angioplasty), peripheral vascular disease, stroke, chronic reversible obstructive lung diseases (e.g., bronchitis or asthma (chronic asthma, allergic asthma)), allergic rhinitis, urticaria, glaucoma, diseases characterized by disorders of gut motility (e.g., irritable bowel syndrome), electile dysfunction (e.g., organic electile dysfunction or psychic electile dysfunction), female sexual dysfunction, impotence, or diabetic complications (e.g., diabetic gangrene, diabetic arthropathy, diabetic glomerulosclerosis, diabetic dermopathy, diabetic neuropathy, diabetic cataract or diabetic retinopathy).
Further, the compounds (I) and pharmaceutically acceptable salts thereof are also useful for the treatment and/or prevention of micturition disorder, incontinence or storage of urine disorder (such as the ones ascribed to nerve regressive affection, inflammation, injury, neoplasm, diabetes mellitus, cerebral vascular accident, surgery, prostatomegaly, urethra relaxation incompetence, dysuria).
It is to be noted that improvement of sexual performance is also included in the treatment of electile dysfunction or impotence.
The compounds (I) and their salts of the present invention have much advantages, such as stronger activity, more suitable half-life, decreased adverse effect, or the like, compared to the known anthranilic acid derivatives having an inhibitory activity of cGMP-PDE, which are shown in the prior arts.
In order to exhibit the usefulness of the present invention, the activities of the compounds (I) are shown in the following.
The test compounds are shown in Tables 1 and 2 and test methods 2 and 3.
cGMP-Phosphodiesterase (PDE) Assay
Human platelet cGMP-PDE was separated from other isozymes in human platelets by a modification of the method of Thompson et. al. (see Cyclic Nucleotide Phosphodiesterase (PDE), in Methods of Enzymatic analysis, Vol 4, p127-234, 1984). In enzyme inhibition assays, the test compounds were dissolved in DMSO and then diluted with assay buffer (50 mM Tris-HCl, 0.077 mg/ml dithiothreitol and 10 mg/ml snake venom, 1 mM EGTA, pH 8.0), at final concentrations ranging from 10xe2x88x9210 to 10xe2x88x926 M. Assays were performed at 0.1 xcexcM substrate ([3H]-cGMP) concentration, at 30xc2x0 C. for 10 minutes using enzyme dilutions which gave 10-20% hydrolysis of substrate. Each assay was initiated by addition of substrate and terminated by addition of anion exchange resin (Dowex(copyright) 1-X8, 250 mg/mg) followed by centrifugation for 10 minutes (3000 rpm, at 4xc2x0 C.). Radioactivity of supernatant (3H-GMP) was assayed by liquid scintillation counting.
The obtained results in enzymatic inhibitory test against human platelet PDE-V are shown in Table 1.
As shown in the above Table 1, the compounds (I) of the present invention have superior inhibitory activity against cGMP-PDE.
The Effect on Erection Function
(a) Effect of Test Compound on Nitroprusside or Ach-induced Relaxation in Isolated Rat Corpora Cavernosa.
Male SD rats were anesthetized with sodium pentobarbital 50 mg/kg intraperitoneally, and the corpora cavernosa was excised. The tunica albuginea was dissected according to the methods described by Italiano et al. (Pharmacological Research, 30, No. 4, 1994) and used for in vitro pharmacological study. The erectile tissue strip was placed in a 25 ml organ bath containing Krebs-Ringer solution. The bath was maintained at 37xc2x0 C. and bubbled with 95% O2 and 5% CO2. The strip was stretched with a resting force of 0.25 g, and isometric contraction were recorded via force development transducer on a recorder.
The strip was equilibrated in the Krebs-Ringer solution for about 60 minutes, and preconstructed by 0.1 mM norepinephrine to ascertain the responsibility of each preparation. The strip was washed several times, and then constricted by 0.1 mM norepinephrine. After getting stable constrictile response to norepinephrine, the first dose-response curve for sodium nitroprusside or Ach(acetylcholine) was obtained. After washing a few times for 60 minutes, the strip was constricted by norepinephrine again, and the second dose-response curve for sodium nitroprusside or Ach was obtained. The test compound, i.e., (R)-N-(3,4-dimethoxybenzyl)-2-(2-hydroxy-1-methylethylamino)-5-nitrobenzamide which was selected as a representative compound of this invention was added 30 minutes before adding norepinephrine. Relaxant response elicited by 10 xcexcM nitroprusside was 20% in control preparation, but this relaxant response increased to 32% in the presence of the test compound (5xc3x9710xe2x88x928 M).
Said compound at 5xc3x9710xe2x88x928 M also potentiated Ach-induced relaxation of corpora cavernosa. 100 xcexcM Ach-induced relaxant response to the contractile response induced by 10xe2x88x924 M norepinephrine was only 5.0% in control preparation, but this relaxant response to Ach increased to 18.0% in the presence of said compound (5xc3x9710xe2x88x928 M).
(b) Effect of test compounds on the relaxation elicited by electrical field stimulation in rabbit corpora cavernosa.
The rabbit erectile tissue strip prepared according to the method described by Italiano et al. (Pharmacological Research, 30, No 4, 1994) was placed 25 ml organ bath containing Krebs-Ringer solution. The bath was maintained at 37xc2x0 C. and bubbled with 95% O2 and 5% CO2. The solution also contained atropine (1 xcexcM) and guanethidine (50 xcexcM). The erectile tissue strip was stretched with a resting force of 0.25 g, and isometric contraction were recorded via force development transducer on a recorder. The bipolar platinum electrode connected to the electric stimulator was placed around the strip.
The strip was equilibrated in the Krebs-Ringer solution for about 60 minutes and preconstricted by 0.1 mM norepinephrine to ascertain the responsibility of each preparation. The strip was washed several times, and then constricted by 0.1 mM norepinephrine. After getting stable contractile response to norepinephrine, the first electrical field stimulation (1 to 30 Hz, 20V, 0.5 msec duration, 90 sec interval) was delivered. 30 minutes after adding the tested compound, the second electrical field stimulation was delivered.
The compounds i.e., N-(3,4-dimethoxybenzyl)-2-(cis-4-hydroxycyclohexylamino)-5-nitrobenzamide and (R)-N-(3,4-dimethoxybenzyl)-2-(2-hydroxy-1-methyl-ethylamino)-5-nitrobenzamide which were selected as representative compounds of this invention, at 5xc3x9710xe2x88x928 M potentiated relaxation of corpora cavernosa elicited by electrical field stimulation in rabbit corpora cavernosa.
Relaxant response elicited by 30 Hz was only 70% in control preparation, but this relaxant response increased to 100% in the presence of 5xc3x9710xe2x88x928 M said compounds.
(c) Male beagle weighing 8.0-12.0 kg were anesthetized with pentobarbital sodium (35 mg/kg, i.v.). After tracheotomy, the animal was artificially ventilated using a volume-cycled ventilator. The femoral artery was cannulated for continuous blood pressure and heart rate monitoring. The femoral vein was cannulated for maintenance of anesthesia and administration of tested compound.
Either the left or right cavernous nerve was exposed posterolaterally to the prostate and a cuff electrode was placed around the nerve for electrical stimulation. A 21-gauge butterfly needle was placed in the corpus cavernousum and connected to a pressure transducer for intracavernous pressure. After a period of stabilization of all parameters, erection was induced by cavernous nerve electrically stimulation (7 Hz, 10 V) and the following was measured: the duration of detumescence (time (T75) from cessation of stimulation to 75% reduction of intracavernous pressure). The test compounds, i.e., N-(3,4-dimethoxybenzyl)-2-(cis-4-hydroxycyclohexylamino)-5-nitrobenzamide and (R)-N-(3,4-dimethoxybenzyl)-2-(2-hydroxy-1-methyl-ethylamino)-5-nitrobenzamide were each dissolved in 50% PEG400. As shown in Table 2, T75 after the cessation of electrical stimulation was prolonged by the administration of the compounds (0.1 mg/kg, i.v.) which were selected as representative compounds of this invention.
Toxicities of Compound (I)
Test on the toxicity by repetitive oral administration of the compounds, i.e., N-(3,4-dimethoxybenzyl)-2-(cis-4-hydroxycyclohexylamino)-5-nitrobenzamide and (R)-N-(3,4-dimethoxybenzyl)-2-(2-hydroxy-1-methylethylamino)-5-nitrobenzamide which were selected as representative compounds of this invention, in SD rat was conducted. The dead at dose of 32 mg/kg once a day for 14 consecutive days could not be observed.
The compound (I) or its salt can be administered alone or in a form of a mixture, preferably, with a pharmaceutical vehicle or carrier.
The active ingredient of this invention can be used in a form of a pharmaceutical preparation, for example, in solid, semisolid or liquid form, which contains a compound (I), as an active ingredient, in admixture with an organic or inorganic carrier or excipient suitable for external, enteral, intravenous, intramuscular, parenteral or intramucous applications. The active ingredient may be compounded, for example, with the conventional non-toxic, pharmaceutically acceptable carriers for ointment, cream, plaster, tablets, pellets, capsules, suppositories, solution (saline, for example), emulsion, suspension (olive oil, for example), aerosols, pills, powders, syrups, injections, troches, cataplasms, aromatic waters, lotions, buccal tablets, sublingual tablets, nasal drops and any other form suitable for use. The carriers which can be used are water, wax, glucose, lactose, gum acacia, gelatin, mannitol, starch paster, magnesium trisilicate, talc, corn starch, keratin, paraffin, colloidal silica, potato starch, urea and other carriers suitable for use in manufacturing preparations, in solid, semisolid, or liquid form, and in addition auxiliary, stabilizing, thickening and coloring agents and perfumes may be used. The active compound is included in a pharmaceutical composition in an effective amount sufficient to produce the desired effect upon the process or condition of the diseases.
The active ingredient may be compounded into, for example, preparations for oral application, preparations for injection, preparations for external application, preparations for inhalation, preparations for application to mucous membranes (oral mucous membrane, fascia penis, facies urethralis penis, etc.).
Mammals which may be treated by the present invention include livestock mammals such as cows, horses, etc., domestic animals such as dogs, cats, rats, etc. and humans, preferably humans.
While the dosage of therapeutically effective amount of a compound (I) varies from and also depends upon the age and condition of each individual patient to be treated, in case of the systemic administration, a daily dose of about 0.01-1000 mg, preferably 0.1-500 mg and more preferably 0.5-100 mg of the active ingredient is generally given for treating the diseases, and an average single dose of about 0.2-0.5 mg, 1 mg, 5 mg, 10 mg, 50 mg, 100 mg, 250 mg and 500 mg is generally administered. Daily doses for chronic administration in humans will be in the range of about 0.3 mg/body to 1,000 mg/body.
The patents, patent applications and publications cited herein above are incorporated by reference.